Random error messages

Question

My Pfaff 7570 is 12 years old. Just noticed random error messages on machine screen... for example now it says "internal error" OK?I'm getting the message each time I stop the machine, as I'm sewing a straight seam, stopping to take out a pin. What a pain.It hasn't affected the sewing - I just press "OK" and keep going. Is this a signal that something is going wrong? Can I do something to clear these error messages.